Set of UI fixes

* Improve wiki pages
* Improve profile pages

cc @skyruler

See merge request !2758

Restrict permissions on public/uploads

Based on https://gitlab.com/gitlab-org/omnibus-gitlab/merge_requests/631

See merge request !2764

Issues can be dragged & dropped into empty milestone lists

This is also possible with MRs. Also fixed an issue where MRs weren't sortable

Fixes #13668

![milestone](/uploads/aada0f48ce8b1407cce920eef3f4d5f3/milestone.gif)

See merge request !2935

Ensure we don't check a commit's description for revert message if it has no description

Fixes #13631.

/cc @razer6 @grzesiek @yorickpeterse @rdavila 

See merge request !2917

Fix Side-by-side view after loading diff results

Fixes #13463

See merge request !2880

Add when the API changes got introduced



See merge request !2912

Fixed failing issues tests

Also removed up/down vote icons from merge requests. Was missed from d8069bd8

See merge request !2911

[ci skip]

Only show up or down votes icon on issue list if there are any

Closes #13649 

![Screen_Shot_2016-02-22_at_10.20.27](/uploads/21477426856dab9731bb110032025867/Screen_Shot_2016-02-22_at_10.20.27.png)

See merge request !2909

Add Todos

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/2425

Tasks:

-  Prepare database
 - [X] Create a new table (`todos`)
- Tasks Queue view
 - [X] Add a number icon showing the number of todos on the top right next to the new and logout button that will redirect the user to the todos page
 - [X] Add a chronological list of todos, with the 'Todos' tab active by default
 - [X] Add a 'Done' button to each todo
 - [x] Add filters (project, author, type, and action)
- Todos generation
 - [X] When user issue/mr is assgined to someone
 - [x] When user is mentioned on (issues/mr's/comments)
- Mark todo as `done`
 - [X] When clicks on the 'Done' button
 - [X] When edit issue/mr
 - [X] When left/edit a comment
 - [X] When reassign issue/mr
 - [X] When add/remove labels to issue/mr
 - [X] When issue/mr is closed
 - [X] When mr is merged
 - [X] When added an emoji
 - [X] When changed the issue/mr milestone

* Screenshot:

![Screenshot_2016-02-20_12.45.57](/uploads/4b2554b1bde25aed3347e1ae41e8e0c0/Screenshot_2016-02-20_12.45.57.png)

See merge request !2817

Fix bugs in MergeWhenSucceeded

1. This fixes support for merge when succeeded for statuses without ref.
2. This fixes support for merge when succeeded for multiple stages. Stages are created after all builds for previous one are finished.

Fixes: https://gitlab.com/gitlab-org/gitlab-ce/issues/9060 https://gitlab.com/gitlab-org/gitlab-ce/issues/8108 https://gitlab.com/gitlab-org/gitlab-ce/issues/12931 https://gitlab.com/gitlab-org/gitlab-ce/issues/13269

/cc @grzesiek @DouweM @rspeicher 


See merge request !2894

Fix docs on artifacts API

Small fixes for https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/2893

- Backticks in parameters
- Remove headings
- Fix curl URL link



See merge request !2902

Award emoji supports retina displays

Based on discussion in !2800

There is now a retina spritesheet for emojis. It is 2mb, don't know how big an issue that is.

Before:

![Screen_Shot_2016-02-19_at_11.07.25](/uploads/ea412579bcaddfd13fce67bf583de61b/Screen_Shot_2016-02-19_at_11.07.25.png)

After:

![Screen_Shot_2016-02-19_at_11.07.36](/uploads/9d44c6278ba31987bad03dc1f46edd8b/Screen_Shot_2016-02-19_at_11.07.36.png)

Also updated the rake task to make the @2x spritesheet https://gitlab.com/snippets/15348

cc\ @rspeicher @vsizov 

See merge request !2891

Flush emptiness caches whenever needed



See merge request !2903

Introduce API for serving the artifacts archive

Add API to download build artifacts archive in context of GitLab API

/cc @DouweM @grzesiek 

See merge request !2893

Add documentation about build emails service

Closes #12497

See merge request !2871

Labels should be visible in milestone view

Closes #3276 

See merge request !2599

Fix missing ignored? for GenericCommitStatus

This is pretty important fix. We should not release 8.5 without this.

It critical error when handling GenericCommitStatus:
```
undefined method `ignored?' for #<GenericCommitStatus:0x007fe1a2a20fe0>
```

cc @grzesiek 


See merge request !2899

revert back to ruby 2.1

- - -

Revert Ruby 2.2 changes - until we solve https://gitlab.com/gitlab-org/gitlab-ce/issues/13514

This also updates Ruby 2.1.7 to 2.1.8

See merge request !2898

Add ability to revert changes introduced by Merge Requests or Commits

Closes #3409 

See merge request !1990

Consistency in MR and issue header.

Fixes: #13550 

![Screen_Shot_2016-02-18_at_11.20.19_AM](/uploads/8327ff045e45029b85b2cbac72c98a7f/Screen_Shot_2016-02-18_at_11.20.19_AM.png)![Screen_Shot_2016-02-18_at_11.20.55_AM](/uploads/f79613ebb23e4a62fb1bdb48d6f7fd2b/Screen_Shot_2016-02-18_at_11.20.55_AM.png)

See merge request !2874

Make it possible to erase build content (artifacts, trace)

This feature makes it possible to remove build content - build artifacts and build traces.

- [x] Remove artifacts
- [x] Remove metadata
- [x] Remove build traces
- [x] Wait for https://dev.gitlab.org/gitlab/gitlabhq/merge_requests/1942 this to be merged
- [x] Fix the permissions after the merge

Closes #3421

See merge request !2560

Mention project name in fork notice

_Originally opened at !1186 by @axil._

- - -

I missed this one in !1070

See merge request !2897

Add runners API

References #4264

See merge request !2640

Put project visibility icon next to title

Fixes #11872

See merge request !2885

Update web editor documentation

Based on https://gitlab.com/gitlab-com/www-gitlab-com/merge_requests/1045

Closes #4262

See merge request !2776

Project limit is reached warning is hidden when the projects_limit is zero

Fixes #12791

See merge request !2890

Update Gemojione for new hotness ✨

Before | After
------ | -----
![Screen_Shot_2016-02-12_at_3.38.43_PM](/uploads/299e5ffe38c91657085741261a678f81/Screen_Shot_2016-02-12_at_3.38.43_PM.png) | ![Screen_Shot_2016-02-12_at_3.38.09_PM](/uploads/ccee29719a6445a9efd2498391a7eea0/Screen_Shot_2016-02-12_at_3.38.09_PM.png)

See merge request !2800

workaround for forks with an invalid repo

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/13465

The error occurs when a project returns a `nil` commit for a variety of reasons, I assume the repository is corrupt - perhaps as a result of a failed fork. 

With this MR, we do not show forks with corrupted repos in the list of forks, as this does not seem to work anyway. A better solution is to fix the cause of the issue and/or any data integrity problem...

Also fixing Sentry issue: 1180
`undefined method 'already_forked?' for nil:NilClass `


See merge request !2836

Allow `ProjectTeam#human_max_access` to return "Owner"



See merge request !2881

Add release tracking for Sentry



See merge request !2863

Use SCAN during 'rake cache:clear'

This allows 'rake cache:clear' to delete millions of keys without
choking. It requires Redis 2.8.0 or newer but we needed that already
anyway.

See merge request !2872

Only set autocrlf when creating/updating files

Related issue: gitlab-org/gitlab-ce#13457
Details: 5619a6de1dd6fc1dfd4053810c7b11c677b7a495

See merge request !2859